ABSTRACT
Fondaparinux sodium is a synthetic low-molecular-weight heparin (LMWH). This medication is an anticoagulant or a blood thinner, prescribed for the treatment of pulmonary embolism and prevention and treatment of deep vein thrombosis. Its determination in the presence of related impurities was studied and validated by a novel ion-pair HPLC method. The separation of the drug and its degradation products was achieved with the polymer-based PLRPs column (250 mm × 4.6 mm; 5 µm) in gradient elution mode. The mixture of 100 mM n-hexylamine and 100 mM acetic acid in water was used as buffer solution. Mobile phase A and mobile phase B were prepared by mixing the buffer and acetonitrile in the ratio of 90:10 (v/v) and 20:80 (v/v), respectively. Mobile phases were delivered in isocratic mode (2% B for 0-5 min) followed by gradient mode (2-85% B in 5-60 min). An Evaporative Light Scattering Detector (ELSD) was connected to the LC system to detect the responses of chromatographic separation. Further, the drug was subjected to stress studies for acidic, basic, oxidative, photolytic, and thermal degradations as per ICH guidelines and the drug was found to be labile in acid, base hydrolysis, and oxidation, while stable in neutral, thermal, and photolytic degradation conditions. The method provided linear responses over the concentration range of the LOQ to 0.30% for each impurity with respect to the analyte concentration of 12.5 mg/mL, and regression analysis showed a correlation coefficient value (r(2)) of more than 0.99 for all the impurities. The LOD and LOQ were found to be 1.4 µg/mL and 4.1 µg/mL, respectively, for fondaparinux. The developed ion-pair method was validated as per ICH guidelines with respect to accuracy, selectivity, precision, linearity, and robustness.
ABSTRACT
A novel, stability-indicating UHPLC method was developed for the quantitative determination of Abacavir sulfate, its related substances, and forced degradation impurities in bulk drugs. The chromatographic separation was achieved on a Waters Acquity BEH C(8), 50 mm × 2.1 mm, 1.7 µm particle size column with a mobile containing a gradient mixture of solution A (0.10 % v/v o-phosphoric acid in water) and solution B (0.10% v/v o-phosphoric acid in methanol). The flow rate was set at 0.40 mL/min and the run time was 6.0 min. The drug substance was subjected to the stress studies of hydrolysis, oxidation, photolysis, and thermal degradation. Abacavir sulfate was found to degrade significantly under acidic hydrolysis and oxidative stress conditions. The formed degradation products were reported and were well-resolved from Abacavir and its related substances. The mass balance was found to be satisfactory in all of the stress conditions, thus proving the stability-indicating capability of the method. The developed UHPLC method was validated to be in agreement with ICH requirements and found to be rapid, accurate, precise, linear, specific, and suitable for the quantitative determination of related substances and degradants in the bulk drug samples of Abacavir sulfate.
ABSTRACT
In the impurity profile of naproxen around 0.6% unknown polar impurity was detected by high performance liquid chromatography (HPLC). The product ion spectrum of the impurity and Naproxen was recorded in LCMS/MS and the fragmentation pattern of the impurity was observed to be similar to the fragmentation pattern of Naproxen with only a difference of two atomic mass units. The high resolution mass spectrum (HRMS) of the impurity displayed a protonated molecular ion at m/z 229.0863, which corresponds to the pseudomolecular formula C(14)H(13)O(3)(+). Based on LC/MS/MS, HRMS, 1D and 2D NMR data, the structure of the impurity was characterized as 2-(6-methoxynaphthalen-2-yl)acrylic acid. The acrylic acid impurity was synthesized in the laboratory and co injected in HPLC to confirm the retention time. RRF of the impurity was determined by (1)H NMR method and also by conventional HPLC slope method and the RRF values are found to be 6.11 and 5.64, respectively. The values are comparable and (1)H NMR method of RRF determination is complimentary and can be effectively used as an alternative method to conventional HPLC method especially in early stages of development when availability of impurity standards is not possible.
